Chapter
2.
Assembly
Language
Concepts
OPERAND FIELD INFORMATION
Information required
Ways
of
specifying
(a)
Register
(1)
Hexadecimal Data
(b)
Register Pair
(2)
Decimal Data
(c)
Immediate Data
(3)
Octal Data
(d) 16-bit Address
(4)
Binary Data
(5) Location
Counter
($)
(6)
ASCII Constant
(7)
Labels assigned values
(8)
Labels
of
instructions or data
(9)
Expressions
Hexadecimal Data. Each hexadecimal number
mu'>l
begin with a numeric digit
(0
through 9) and must
be
followed
by
the letter
H.
Label Opcode Operand
Comment
HERE: MVI
C,OBAH
;LOAD
REG
C
WITH
HEX
BA
Decima! Data. Each decimal number
may
be
identified
by
the letter D immediately after its last digit or may
stand alone. Any number not specifically identified
as
hexadecimal, octal,
or
binary
is
assumed to
be
decimal.
Thus, the following statements are equivalent:
Label
ABC:
Opcode
MVI
MVI
Operand
E,15
E,15D
Comment
;LOAD E WITH 15 DECIMAL
Octo! Data. Each octal number must be followed
by
the letter 0 or the letter
O.
Lobe! Opcode
Operand
LABEL:
MVI
A,720
Binary Data. Each binary number must
be
followed
by
the letter
B.
Lobe!
Opcode
Operand
NOW:
MVI
D,11110110B
Comment
;LOAD OCTAL 72 INTO
ACCUM
Comment
;LOAD REGISTER D
;WITH
OF6H
2-5
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